A Comparison of Global MDOF and Local SDOF Curve-Fitting Algorithms for The Identification of Close Modes

摘要

This paper reports results obtained from a global multi-degree-of-freedom (MDOF) modal analysis technique when applied to analytically-generated frequency response functions (FRFs) exhibiting two close modes. Particular, attention is paid to cases where there are natural frequency shifts from one FRF to the next due to systematic measurement errors and to the effect of noise on measured data. Wherever possible, results from global analyses are checked against those obtained from single-degree-of-freedom (SDOF) methods in order to highlight the relative advantages and shortcomings of each analysis method as well as to assess the reliability and the general applicability of the global MDOF techniques.